Essay on the evolution of adult-parasitism in the subfamily Euphorinae (Hymenoptera: Braconidae)

The phenomenon of adult-parasitism by the euphorine Braconidae is characterized and dis- cussed. Hypotheses regarding the evolution of adult-parasitism are outlined. It is suggested that adult- parasitism arose from ancestors that were koinobiont larval-larval parasitoids, but never from idiobiosis directly, because koinobionts evolved rapid oviposition behavior necessary as a pre-adaptation for attack- ing mobile adult insects. Adult parasitoids are shown to have a unique combination of koinobiont and idiobiont characteristics. The new terms, imagobiosis and imagophagy, are proposed for characterization of those koinobionts that have specialized for attacking adult insects. The implications of the imagobiont strategy relative to diversity patterns in the tropics are discussed.